A few recent studies with weak design sought a link between pediatric obesity and method of delivery: vaginal birth versus cesarean section.

Confirmation bias typically arises from seeking information that confirms your predetermined hypothesis. To simplify: what you seek, you shall find.

So gave birth to the notion that there could be causality or at a minimum a link between Cesarean Delivery (CD) and the development of childhood obesity. The reality is rates for both have been on the rise in recent decades which is why pursuing a magic bullet relationship holds appeal.

Researchers “examined the development of BMI (body mass index) from birth through childhood to determine whether CDs were associated with differences in growth and obesity.” Using term children from birth cohorts Copenhagen Prospective Studies on Asthma in Childhood (COPSAC 2000 & 2010), the team determined “there were no differences in BMI trajectory…by 5 and 13 years, nor cross-sectional BMI at 5 and 13 years, nor in fat percentages from the DXA (dual-energy x-ray absorptiometry) scans.”

They conclude: “Children delivered by CD had a higher mean BMI at 6 months of age, but this difference did not track into later childhood. Our study does not support the hypothesis that CD leads to later overweight.” Further pertinent findings from their work:

The mothers born by CD were older.

Children born by CD had a lower gestational age (aka were younger).

Children delivered by CD had higher standardized birth weight for gestational age and a shorter duration of exclusive breastfeeding (seen in COPSAC 2010, not 2000).

Mothers who delivered by CD (2010 group) had higher prepregnancy BMI and more likely to be nulliparous— a woman who has not given birth.

No significant association in BMI or body composition in childhood/puberty and delivery mode—no risk of being overweight in later childhood.

Much of prior scant work on the topic lacked vital details like maternal prepregnancy weight, gestational diabetes status, type of feeding (e.g. breastmilk or formula) etc. Why does that matter? These are essential factors that influence decision-making to section a pregnant mother in the first place and substantially contribute to the weight discussion.

Maternal history is baby’s history. Without knowledge of mom’s prepregnancy status or baby’s feeding specifics, for example, accurately determining an association between delivery mode and future obesity is wrought with deficiencies.

Since pediatric obesity—and obesity, in general— has a multifactorial, complex etiology, searching for a singular cause makes everyone’s world easier. But, life is a bit more messy and complicated. Genetics, environment, medical history, lifestyle and behavioral facets (among others) play a role.

Placing this and past studies into context is crucial to understanding the bigger picture. Now we can explore some reasons why an infant born via c-section having a greater BMI in the first 6 months compared to those with vaginal deliveries makes a lot of sense. As does the fact weights evened out so quickly thereafter and throughout childhood. While a few previous studies attempted to determine causality of CD as the inciting event for later childhood obesity, I will underscore why dismissing valuable details impedes such conclusions.

For example, we know babies born to mothers with gestational diabetes have a higher risk of becoming overweight or developing Type 2 Diabetes. A baby in this scenario, in particular when sub-optimally controlled, will tend to be larger. This macrosomia (aka large body) can pose a challenge to vaginal birth, so is often more likely to be born via CD. Regardless of delivery mode, this infant carries greater risk of being overweight than his contemporary not born under poorly controlled diabetes of pregnancy.

The CD is not the main culprit here, the history is.

We are speaking of risk stratification, not certainty or guarantee. Fortunately, there are preventive measures that can be quite successful which is why a complete history is so critical.

Hence, knowing this status is vital to interpreting any real or imagined correlation. As is the mechanism of infant feeding. The benefit with formula in teasing out growth is the fact that we know the caloric content of each type due to standardization in manufacturing, so can precisely monitor intake. In terms of the breastfed infant, though volume can be sufficiently maintained by the mother if she is calorie-deficient but well-hydrated the breastmilk will be nutritionally deficient. Knowing its calorie content requires laboratory analysis since it is not the same between individuals. This is an inefficient and often impractical exercise, so following infant growth or lack thereof is the more practical measure. How and what an infant eats tells much of the story.

Additionally, it is typically harder to overfeed a breastfed baby than a formula-fed one. The tendency to placate an infant with feeds is quite common since at this developmental phase the baby cannot verbally convey his needs. Whether a mother breastfeeds or not is a personal decision that can be influenced by a wide range of considerations like medical concerns for her or the newborn to a complicated post-surgical course to individual preference.

Such are some explanations as to why the mean BMI growth diversion in the first 6 months of life.

Whether an infant receives breast milk or formula can often depend on the early period after birth. Since the act of CD especially in a first time mother can delay milk production, early formula supplementation routinely takes place. The body has memory, so for a first-time mom there won’t be this benefit. In the situation of the infant born to a diabetic mother, birth marks an abrupt cessation of higher levels of glucose—or blood sugar—and these babies can have issues with low blood sugar (e.g. hypoglycemia) so require early feeding for therapeutic purposes. Since mom’s milk is not in during this period, formula can be most effective in the newborn with hypoglycemia.

This is one mere instance where underlying issues prompted the c-section in a population with a higher risk for future obesity. The babies born here are usually heavier. So, remaining so in the first few months especially if formula fed would be expected.

The first year of life—but especially the first six months —should reflect the most rapid growth rate for babies no matter the mode. In the first six months, the baby takes in calories but doesn’t go to the gym since developmentally they can’t do much physically. They barely work out except during a feed. Around and approaching the six month point, they begin to become more vigorous, sitting up, flailing around, rolling over etc. Because they encounter a personality explosion and are very stimulated by the world around them, they start to take in less breast milk or formula and burn more calories from their enhanced mobility. So, leaning out in the 6-9 month span is common.

So, what’s the real deal about the health risks or benefits of c-sections versus vaginal births?

The real deal is as nature intended, when possible, is in the best interest of the infant and mother. However, possessing the ability to perform a c-section to ensure the healthiest outcome for mother and child is a true gift of modern medical advancement. Determining which mode is safest for the clinical situation at hand, requires real-time case-by-case assessment. Looking at a medical record after the fact will not do justice to the issue.

There can be differences in the perinatal period for the baby depending upon which avenue is taken. C-sections abort the process of traveling through the birth canal which readies infants for their first breath, so these babies are more prone to transient tachypnea of the newborn which is a mechanical and physiological issue —due to the complexity of the perinatal circulation, for instance. This is routinely addressed and more commonly the babies recover quickly requiring little support. Long-term significance depends on how substantial the lung condition is from that period and what interventions took place. Some might be preterm, for example, where degree of lung immaturity can contribute to problems down the line.

C-sections can, as previously discussed, delay a mother’s milk production, protract her recovery, impact future pregnancies and bring about issues that accompany a post-operative period, in general. The decision to do so— when there is time to make one— should be informed and convenience not be the presiding motivator.

When it is medically in her and/or the child’s best interest, it is an effective and ideal option that can secure their well-being. Pregnancy designs the most sophisticated suspension system there is that creates a symbiotic relationship where comprehensive understanding must guide delivery choice.

Mode of delivery does not guarantee future obesity, or at least that is not what the evidence supports today. Focusing on the situations we can control like altering our lifestyles to include a healthier diet and regular exercise will hold greater success in winning the battle against being overweight or obese.

Dr. Jamie Wells, MD, FAAP, is an award-winning Board-Certified physician with over a decade of experience caring for patients and the Director of Medicine at the American Council on Science and Health. She served as a Clinical Instructor/Attending at NYU Langone, Mt. Sinai-Beth Israel and St. Vincent's Medical Centers in Manhattan. Dr. Wells graduated from Yale University with honors, was inducted as a junior and elected President of Jefferson Medical College's Alpha Omega Alpha National Medical Honor Society and has been named a New York Super Doctor, repeatedly, in the NY Times magazine supplement listing the top 5% of physicians in over 30 medical specialties as chosen by their peers.
A National Merit Scholar, Dr. Wells was identified for her academic excellence early on when she was selected by the Center for Excellence in Education (CEE) for its prestigious Research Science Institute (RSI) and was featured as one of the top twenty high school students in the nation in USA TODAY as a recipient of their scholarship. At Yale, she was President of the Yale Science and Engineering Association, majored in American Studies and concentrated in media and film, spending her final year researching her senior essay entitled, "Ebola: The Making of an Epidemic"-- exploring the power of the governmental, political, public health and media machines and their desire to work in harmony when there is a common economic concern. In medical school, she maintained various leadership and elected positions (such as Editorials Editor of the school paper and editing guides to passing Board Exams) while creating mentoring and tutoring programs and spearheading countless volunteer activities that served the school and local Philadelphia communities. During this time, she did research for the Department of Neurosurgery at the University of Pennsylvania School of Medicine in deep brain stimulation of the subthalamic nucleus of patients with Essential Tremor and Parkinson's Disease.
She was a grant reviewer for Komen's 2018-2019 Community Grants Program and has judged the local, district and world championships for Dean Kamen’s F.I.R.S.T. (For Inspiration & Recognition of Science & Technology) robotics competition as well as the Miss America’s Outstanding Teen scholarship competition for which she was recently nominated and, subsequently, elected to be a member of its Board of Directors. Dr. Wells is on the Leadership Council of The Wistar Institute (the nation's first independent biomedical research facility and certified cancer center) and is a Visiting Fellow at the Independent Women's Forum. She has been awarded America's Top Pediatricians, America’s Top Physicians Honors of Distinction and Excellence, Compassionate Doctors Award, Patients Choice Award (honors given by patients to less than 3% of the nation's 720,000 active physicians) and been recognized for her exemplary care of those with Cystic Fibrosis. Dr. Wells was named a Doctor of Excellence which profiles the world’s leading doctors who have demonstrated success and leadership in their profession. For the better part of a decade, she answered all of the medical inquiries on line for the Boomer Esiason Cystic Fibrosis Foundation's website in a section entitled, ASK DR. WELLS.
Whether she is published, for example, in the acclaimed journal Neoreviews for a case involving a near drowning of an infant via water birth, USA Today regarding the mysterious illness of US diplomats in Cuba or the Huffington Post in response to the Dolce & Gabbana controversy or 10 ways to Save Your Life or the Life of a Loved One, it is a longstanding passion of hers to make science and health understanding accessible to all. She champions empowering others to be their own advocate in healthcare and has given talks to various audiences from struggling expectant mothers and parenting groups to undergraduates, spoken on panels as well as emphasized education to patients under her care. Believing she wanted to be a brain surgeon, she began her first residency in neurosurgery, ultimately switching fields to pediatrics. As a result, her knowledge is vast in the medical realm and sought after by innumerable media outlets.
Dr. Wells’ greatest asset is making complicated material palatable for people in a nonthreatening, often humorous way. Her opinion as a medical expert has been showcased on live and taped local, national and international television programs that run the gamut from CNN, Fox National News Channel, ABC News, BBC, Reuters, Al Jazeera TV, NY 1, CBS, TLC, Fox Business Network, Fox 5, Parent TV, CUNY-TV, My 9, Arise TV and so on having been featured in an hour length show on Discovery Health and, repeatedly, on Sirius Radio for Martha Stewart Living. She is a huge proponent of the health benefits of animals and was certified with her adorable and gifted English Bulldog, Mollie Joe, as a therapy team.
We asked New York City to guess her profession and no one got it right:

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